Heat dissipating module with three-dimensional structure

ABSTRACT

A heat dissipating module with three-dimensional structure includes a heat dissipating cavity connecting to a top of a heat absorbing cavity to form a distance from a heat source. When a working fluid in the heat absorbing cavity absorbs the thermal energy and is vaporized, the vapor would flow up to a vapor guiding space due to thermosyphon effect and principles of Boyle&#39;s Law, and then the vapor is projected and spread rapidly and evenly to the heat dissipating cavity through a projecting exit. Then the vapor is condensed into liquid and become the working fluid again by heat exchange. The condensed liquid then drips down and flows back to the heat absorbing cavity via micro-passages, forming a cycle of phase change of the working fluid for operation of heat dissipation.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention relates to a heat dissipating module, especially to one that has a three-dimensional structure and forms a distance from the heat source to the dissipating fins.

2. Description of the Related Art

As technology advanced, nowadays the chips installed on electronic devices have increased, causing higher temperature of the devices during operations. To avoid problems resulted from high temperature, heat pipes are commonly used in the field for heat dissipation. Such heat pipes conduct and transfer the thermal energy by the latent heat produced from phase changes of the working fluids. At the vaporization section of the heat pipes, the working fluids obtain a huge amount of thermal energy from the heat source by vaporizing the latent heat and then release the thermal energy and condense into liquid at the condensation section of the heat pipes. The working fluids would flow back to the vaporization section due to the wick structure and capillary actions of liquids. Such operation is repeated within the heat pipes for continuous heat dissipation.

FIG. 1 illustrated a conventional heat dissipating module 10 in one-dimension. The module 10 has a plurality of dissipating fins 12 arranged at a rear end of a pipe 11 and has a front end extended to have contact with a heating device (not shown). When the front end absorbs the thermal energy from the heating device, the energy is transmitted to the rear end for dissipating the heat by the dissipating fins 12. Although such operation can dissipate the heat in some degree, it cannot achieve certain efficiency since the rear end of the pipe 11 has the worst thermal conductivity. On the other hand, due to the design of the pipe 11, the working fluid inside the pipe 11 would stay at the rear end when going through phase changes, and the thermal energy cannot be conducted and transferred to the fins 12 effectively, causing ineffective results of the dissipation.

FIG. 2 illustrated a conventional heat dissipating module 20 in two-dimension. The module 20 mainly includes an upper board 21 and a lower board 22, and the surface of the upper board 21 are chipped and cut to form a plurality of dissipating find 23. When the upper and lower boards 21, 22 are assembled, a hollow chamber 24 is formed therein, so that when the lower board 22 is contacting with a heating device (not shown), the thermal energy would be absorbed by the lower board 22 and conducted to the upper board 21 via the hollow chamber 24. Then the thermal energy is further conducted and transferred to the fins 23 for dissipation. Such modules do have greater efficiency than the one shown in FIG. 1, but as the power of electronic devices such as light-emitting diodes getting higher and being applied to huge devices like fishing light attractors, lighting projectors and projectors, the dissipating efficiency of such modules still requires improvements.

SUMMARY OF THE INVENTION

It is a primary objective of the present invention to provide a heat dissipating module with three-dimensional structure for a heat dissipating section to be arranged at a distance from a heat source, so as to enhance the heat dissipation function and reduce the side effects that conventional heat dissipation modules may cause to the applied products.

It is another objective of the present invention to provide a heat dissipating module with three-dimensional structure that makes use of the principles of thermosyphon and Boyle's Law to project vapor rapidly and evenly for heat dissipation.

In order to achieve the above objectives, the heat dissipating module with three-dimensional structure includes a heat absorbing cavity vertically arranged as a bottom section thereof arranged to be contacted with a heat source and a first opening arranged at a top section thereof to form a connecting space between said bottom section of said heat absorbing cavity and said first opening; a vapor guiding chamber arranged in said connecting space near said first opening and including a cover board arranged in a shape corresponding to an inner periphery of said connecting space for said cover board to be fixed in said connecting space near said first opening, at a center of said cover board, a second opening being arranged with an outer diameter shorter than an inner diameter of said connecting space to form a projecting exit and a vapor guiding space vertically arranged in a middle of said heat absorbing cavity filled with a working fluid; a heat dissipating cavity connecting said opening of said heat absorbing cavity and further connecting with said projecting exit of said heat absorbing cavity, thereby being far from said bottom section of said heat absorbing cavity, said heat dissipating cavity including a plurality of fins on a top surface thereof for heat dissipation; at least one layer of capillary structure vertically arranged on an inner periphery wall of said heat absorbing cavity, an upper section thereof connecting said heat dissipating cavity and a lower section thereof connecting said bottom section of said heat absorbing cavity, thereby forming a micro-passage structure.

Whereby when the working fluid absorbs the thermal energy from the heat source, the working fluid is vaporized and the vapor is guided to flow upwards through the vapor guiding space and then, based on the thermosyphon effect, projected from the projecting exit and spread rapidly and evenly to the heat dissipating cavity for the fins to perform heat dissipation; then the vapor in the heat dissipating cavity further goes through a heat exchange process and is condensed back to liquid form for dripping and flowing back to the heat absorbing cavity by the micro-passage structure via the upper section and then the lower section of the capillary structure layer and becoming the working fluid again, so as to form a cycle of the heat dissipating module.

In a preferred embodiment, the layer of capillary structure has a flange surface for the cover board to be disposed thereon, further defining the vapor guiding chamber.

In an applicable embodiment, the cover board is a flat board with a conic hole arranged in the middle thereof, an upper part of said conic hole having a substantially shorter diameter and a lower part having a substantially longer diameter. In another applicable embodiment, the cover board is a hollow conic section with the second opening arranged at a top of the hollow conic section.

In an applicable embodiment, a micro structure is further arranged on an inner periphery of the hollow conic section; in another applicable embodiment, a helix structure is further arranged on an inner periphery of the hollow conic section.

In an applicable embodiment, another layer of capillary structure is horizontally arranged on a bottom surface of the heat absorbing cavity; both layers of capillary structure are formed by microporous structure arranged on an inner periphery of the heat absorbing cavity, and a lower end of the vertically arranged capillary structure layer is either connecting or not connecting to the horizontally arranged capillary structure layer.

With the structures disclosed, the bottom section of the heat absorbing cavity includes a bottom surface and a periphery extended upwards from said bottom surface in order to be contacted with different heat sources.

Based on the thermosyphon effect and the principles of Boyle's Law, the present invention has the vapor flow upwards to the heat dissipating cavity rapidly and evenly through the vapor guiding chamber to be projected from the projecting exit. And the structure of the heat dissipating cavity being arranged at a distance from the heat source features even greater efficiency in heat dissipation and less side effects to the products it is installed on during operation. The present invention is thereby suitable for LED lighting fixtures and electronic devices with high power rates.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating structure of a one-dimensional heat dissipating module according to the prior art;

FIG. 2 is a schematic diagram illustrating structure of a two-dimensional heat dissipating module according to the prior art;

FIG. 3 is a schematic diagram illustrating structure of the present invention in a preferred embodiment;

FIG. 4 is a schematic diagram illustrating a working fluid vaporized in the preferred embodiment;

FIG. 5 is a schematic diagram illustrating vapor condensed to liquid and flowing back to become the working fluid again, thereby forming a cycle of phase change according to the preferred embodiment;

FIG. 6 is a schematic diagram illustrating operation of a projecting exit of the present invention in the preferred embodiment;

FIG. 7 is an enlarged diagram illustrating partial structure of the present invention;

FIG. 8 is a schematic diagram illustrating a vapor guiding section of the present invention in an applicable embodiment;

FIG. 9 is a schematic diagram illustrating the vapor guiding section of the present invention in another applicable embodiment; and

FIG. 10 is a schematic diagram illustrating the vapor guiding section of the present invention in yet another applicable embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 3-6, in a first applicable embodiment, a heat dissipating module with micro-passages 50 mainly includes a heat absorbing cavity 30, a vapor guiding section 34, a heat dissipating cavity 40 and at least a layer of capillary structure 36.

The heat absorbing cavity 30 is vertically arranged as a bottom section 31 thereof arranged to be contacted with a heat source H and a first opening 32 arranged at a top section thereof to form a connecting space 33 between the bottom section 31 of the heat absorbing cavity 30 and the first opening 32. In this embodiment, the bottom section 31 includes a bottom surface and a periphery extended upwards from the bottom surface in order to be contacted with different heat sources.

The vapor guiding chamber 34 is arranged in the connecting space 33 near the first opening 32 and includes a cover board 341 arranged in a shape corresponding to an inner periphery of the connecting space 33 for the cover board 341 to be fixed in the connecting space 33 near the first opening 32. At a center of the cover board 341, a second opening 342 a is arranged with an outer diameter shorter than an inner diameter of the connecting space 33 to form a projecting exit 342 and a vapor guiding space 35 vertically arranged in a middle of the heat absorbing cavity 30 filled with a working fluid W. In this embodiment, the shape of the heat absorbing cavity 30 can be circular or polygonal and the projecting exit 33 of the vapor guiding chamber 34 is the second opening 342 a at the center of the cover board 341; the cover board 341 is a flat board 341 a as shown in FIGS. 3-6.

The heat dissipating cavity 40 is connecting to the first opening 32 of the heat absorbing cavity 30 and further connecting with the projecting exit 342 of the heat absorbing cavity 30, thereby being far from the bottom section 31 of the heat absorbing cavity 30. The heat dissipating cavity 40 further includes a plurality of fins 41 on a top surface thereof for heat dissipation. In this embodiment, the shape of the heat dissipating cavity 40 is arranged in accordance with the shape of the heat absorbing cavity 30.

The at least one layer of capillary structure 36 is vertically arranged on an inner periphery wall of the heat absorbing cavity 30 and has an upper section 361 connecting the heat dissipating cavity 40 and a lower section 362 connecting the bottom section 31 of the heat absorbing cavity 30, thereby forming a micro-passage structure. In this embodiment, the layer of capillary structure 36 has a flange surface 363 for the cover board 341 to be disposed thereon, further defining the vapor guiding chamber 35, but the present invention is not limited to such application. The cover board 341 can be bonded, engaged or fixed above the vapor guiding chamber 35 in any other way.

In a preferred embodiment, another layer of capillary structure 37 is horizontally arranged on a bottom surface of the heat absorbing cavity 30. Further referring to FIG. 7, both layers of capillary structure 36, 37 are formed by microporous structure arranged on an inner periphery of the heat absorbing cavity 30. The microporous structure is formed by sintering to form the micro-passage structure for capillary action. In this embodiment, a lower end 362 of the vertically arranged capillary structure layer 36 is not connecting to the horizontally arranged capillary structure layer 37, but having both layers connecting is also applicable in the present invention (not shown). The horizontally arranged capillary structure layer 37 is arranged for the working fluid W to infiltrate and for controlling the vaporization rate of the working fluid W.

With structures disclosed above, when the working fluid W absorbs the thermal energy from the heat source H, the working fluid W is vaporized and the vapor V is guided to flow upwards through the vapor guiding space 35 and then projected from the projecting exit 342 and spread rapidly and evenly to the heat dissipating cavity 40 for the fins 41 to perform heat dissipation based on the thermosyphon effect; then the vapor V in the heat dissipating cavity 40 further goes through a heat exchange process and is condensed back to liquid form L; by the micro-passage structure, the liquid L would drip and flow back to the heat absorbing cavity 30 via the upper section 361 and then the lower section 362 of the vertical capillary structure 36 and becoming the working fluid W again, so as to form a cycle of phase change for operation of the heat dissipating module 50.

The working fluid W is selected from a group including pure water, ammonia solution, methyl alcohol, isopropyl alcohol and heptane liquid; it is also applicable to add heat conductive particles in the working fluid W to enhance the dissipation function. Such particles include copper particles, carbon nanotube, carbon nanocapsules, and the carbon nanotube and the carbon nanocapsules may further contain copper particles in nanometer degrees filled therein. But the present invention is not limited to such application.

In this embodiment, the route for the condensed liquid L to flow back to the heat absorbing cavity 30 is formed by the vertically arranged capillary structure layer 36 on the inner periphery of the heat absorbing cavity 36. After the vapor V is condensed to liquid form L, the liquid L would drip and flow back down to the heat absorbing cavity 30 due to the gravity force and capillary phenomenon. Therefore, there is no need for further arrangement of one-way valves for ensuring the liquid L to flow back. The design of the present invention combines the thermosyphon effects and principles of Boyle's Law and has the projecting exit 342 for the vapor V to be projected upwards with high pressure; hence, there is little possibility that the working fluid W would reversely flow up from the lower section 362 of the vertical capillary structure layer 36.

Referring to FIGS. 4 and 5, when the working fluid W absorbs the thermal energy from the heat source H, the working fluid W is vaporized and the vapor V is guided to flow upwards through the vapor guiding space 35 and then projected from the projecting exit 342 and spread rapidly and evenly to the heat dissipating cavity 40 for the fins 41 to perform heat dissipation based on the thermosyphon effect; then the vapor V in the heat dissipating cavity 40 further goes through a heat exchange process and is condensed back to liquid form L; by the micro-passage structure, the liquid L would drip and flow back to the heat absorbing cavity 30 via the upper section 361 and then the lower section 362 of the vertical capillary structure 36 and becoming the working fluid W again, so as to form a cycle of phase change for operation of the heat dissipating module 50.

The thermosyphon is the process of producing a pushing force by density difference. The density difference is further formed by heating up the working fluid W by a heating source H to cause partial of the working fluid W vaporized and thereby reducing the density. When the working fluid W is heated, its volume is increased and its weight is also lighter, causing a rising phenomenon; then the colder fluid nearby would fill in the space and thereby form the cycle to produce the force repeatedly.

Referring to FIG. 6, according to the compressibility of air and the Boyle's Law, the volume of compressible air is in inverse proportion to the force of pressure; and the design of the projecting exit 33 is exactly a structure of a compressor for the vapor V in the vapor guiding space 32. The vapor V is thereby projected and spread rapidly and evenly from the projecting exit 33 due to sudden change of the pressure and the volume caused by the density difference. Then the vapor V is further spread in the heat dissipating cavity 40 for the fins 41 to perform dissipation efficiently.

Further referring to FIG. 8, in another applicable embodiment, the cover board 341 is a flat board 341 a with a conic hole 342 b arranged in the middle thereof; an upper part of the conic hole 342 b has a substantially shorter diameter and a lower part thereof has a substantially longer diameter.

Referring to FIG. 9, in another applicable embodiment, the cover board 341 is a hollow conic section 341 b with the second opening 342 a arranged at a top of the hollow conic section 341 b, and a micro structure 343 is further arranged on an inner periphery of the hollow conic section 341 b. With the micro structure 343, the vapor V would flow through the vapor guiding section 34 more smoothly and would be spread out rapidly and evenly after being projected from the projecting exit 342 for better efficiency in heat dissipation.

In another applicable embodiment as shown in FIG. 10, a helix structure 344 is further arranged on an inner periphery of the hollow conic section 341b. The helix structure 344 is like the rifling on the inner surface of a gun's barrel to allow the vapor V to spin within the vapor guiding section 34 and then to be further projected from the projecting exit 342. With the spinning movement, the vapor V can be spread rapidly and evenly for greater efficiency of dissipation.

In short, the structure of the heat dissipating module 50 combines the thermosyphon effect and the design of the projecting exit 342 based on Boyle's Law to guide the vapor produced from heated working fluid W flowing upwards through the vapor guiding chamber 35, being projected from the projecting exit 342 and spread to the heat dissipating cavity 40 rapidly and evenly. Such design can dissipate the heat efficiently and is especially suitable for LED lighting fixtures and electronic devices with high power. Additionally, the heat dissipating cavity 40 is arranged at a distance from the heat source H to enhance the efficiency of dissipation and to reduce the side effects the module might cause to the products it is installed on, further controlling the temperature in some degree.

Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims. 

What is claimed is:
 1. A heat dissipating module with three-dimensional structure, comprising: a heat absorbing cavity vertically arranged as a bottom section thereof arranged to be contacted with a heat source and a first opening arranged at a top section thereof to form a connecting space between said bottom section of said heat absorbing cavity and said first opening; a vapor guiding chamber arranged in said connecting space near said first opening and including a cover board arranged in a shape corresponding to an inner periphery of said connecting space for said cover board to be fixed in said connecting space near said first opening, at a center of said cover board, a second opening being arranged with an outer diameter shorter than an inner diameter of said connecting space to form a projecting exit and a vapor guiding space vertically arranged in a middle of said heat absorbing cavity filled with a working fluid; a heat dissipating cavity connecting said opening of said heat absorbing cavity and further connecting with said projecting exit of said heat absorbing cavity, thereby being far from said bottom section of said heat absorbing cavity, said heat dissipating cavity including a plurality of fins on a top surface thereof for heat dissipation; at least one layer of capillary structure vertically arranged on an inner periphery wall of said heat absorbing cavity, an upper section thereof connecting said heat dissipating cavity and a lower section thereof connecting said bottom section of said heat absorbing cavity, thereby forming a micro-passage structure; whereby when the working fluid absorbs the thermal energy from the heat source, the working fluid is vaporized and the vapor is guided to flow upwards through the vapor guiding space and then projected from the projecting exit and spread rapidly and evenly to the heat dissipating cavity for the fins to perform heat dissipation; then the vapor in the heat dissipating cavity further goes through a heat exchange process and is condensed back to liquid form for dripping and flowing back to the heat absorbing cavity by the micro-passage structure via the upper section and then the lower section of the capillary structure layer and becoming the working fluid again, so as to form a cycle of the heat dissipating module.
 2. The heat dissipating module with three-dimensional structure as claimed in claim 1, wherein the layer of capillary structure has a flange surface for the cover board to be disposed thereon, further defining the vapor guiding chamber.
 3. The heat dissipating module with three-dimensional structure as claimed in claim 2, wherein the cover board is a flat board with a conic hole arranged in the middle thereof, an upper part of said conic hole having a substantially shorter diameter and a lower part having a substantially longer diameter.
 4. The heat dissipating module with three-dimensional structure as claimed in claim 2, wherein the cover board is a hollow conic section with the second opening arranged at a top of the hollow conic section.
 5. The heat dissipating module with three-dimensional structure as claimed in claim 4, wherein a micro structure is further arranged on an inner periphery of the hollow conic section.
 6. The heat dissipating module with three-dimensional structure as claimed in claim 4, wherein a helix structure is further arranged on an inner periphery of the hollow conic section.
 7. The heat dissipating module with three-dimensional structure as claimed in claim 1, wherein another layer of capillary structure is horizontally arranged on a bottom surface of the heat absorbing cavity.
 8. The heat dissipating module with three-dimensional structure as claimed in claim 7, wherein both layers of capillary structure are formed by microporous structure arranged on an inner periphery of the heat absorbing cavity.
 9. The heat dissipating module with three-dimensional structure as claimed in claim 8, wherein a lower end of the vertically arranged capillary structure layer is either connecting or not connecting to the horizontally arranged capillary structure layer.
 10. The heat dissipating module with three-dimensional structure as claimed in claim 1, wherein the bottom section of the heat absorbing cavity includes a bottom surface and a periphery extended upwards from said bottom surface in order to be contacted with different heat sources. 